No not that Climatology

Well, back to writing some posts. A fellow I know needed me to help him move some cattle. That meant quite a bit of time in the saddle, and then hauling winter feed to the new location. Oh great I get to ride drag, and no that doesn't mean riding in women's clothes. It's where you get to smell the cow flatulence all day and eat dust for hours on end at the back of the drive.

I have worked with a lot of people over the years in what I call planetary sciences. This also includes atmospheric research. Over the years I have built a number of instruments and conducted experimental studies in support of this type of work so I naturally developed an interest in the subject. One aspect of this field is obviously the climate of earth both in the past and the present. The present day arguments over modern climate change don't hold much interest for me but the past or paleoclimate studies do. 

What Do You Believe?

Given our last election and some of the rather unusual events I thought I would create a mathematical model to explore this strange space. So the first thing to do is to express the thing in some form and see if it makes sense. An exponential model first comes to mind such as:

Explosives Applications: The Shaped Charge

One major use for explosives is in the oil and gas industry to complete a well. For a simple well the process is straightforward. The well is drilled, cased and then perforated. This involves inserting a length of tubing with a series of shaped charges along it's length into the cased well and setting off the charges that perforate the casing and the oil and gas bearing strata.

A shaped charge in its simplest form is nothing more than a metal cone surrounded by explosives. The charge is end initiated and the explosive collapses the conical liner into a jet of material that penetrates at very high velocity. The jet penetrates in the same manner as I previously posted about hypervelocity penetration. A model of a simple 65 degree angled shaped charge is shown in the first video. As the detonation proceeds up the charge the cone collapses inward in a symmetrical manner with an upwards momentum. At the collision point the cone coalesces into a jet of material that has a high velocity and has a final form of a long slender rod.

Over the Hills and Through The Woods...

It's getting close to that time of the year when the snow flies. I like to hit the mountains once there is a fair amount of snow. These pictures are from last winter after the first storm. There was 3 feet of snow in that storm. That's me snowshoeing in (uphill, both ways) with a sleigh full of supplies.

Mush, Mush I say.

Sweet Seclusion.

It's always enjoyable to be up there when the snow is coming down. I'm at about 7000' and just below the ridgeline so the clouds pile up there during a snowstorm. The snow crystals form right in front of your eyes and then fall just a few feet to the ground. It's odd, but quite mesmerizing.

How About a Nice Curve Fit?

I've been meaning to do this for some time. That is developing a Windows based system for fitting equation of state terms to experimental data, rather then relying on other people's fitting routines. One of the more common equations of state (P-v relationship) people like to use in the explosives world is the Jones-Wilkins-Lee (JWL) equation of state. There are others but I won't go into them for now. One form of the JWL equation of state for the products of detonation is given by:

The data to fit to has to be in an Excel file and can be imported directly into the application. The data file needs to be in the form displayed. The pressure units are in GPa.

A Digression of Sorts

I spend most of my time here talking about technology, and acquiring and using one's skills. What I haven't really talked about is the why. Why study this, why learn this, why write about it? The why is just as important as the how. I firmly believe humans are meant to explore and build. We also have a tremendous desire to determine how it all fits together and where we stand within it. Our science, art, religion, and our very cultures are a reflection of this desire. We also have a need to understand the way things work so that we may prosper as an individual and as a species. Anything that furthers this goal of knowing we undertake. Sometimes for better, sometimes for worse.

The Covid-19 pandemic is an excellent example and has brought a few things into better focus for me. I have worked my whole adult life around hazardous materials and under hazardous conditions. It's not my death or injury that concerns me, I'm used to taking that into account. A pandemic, and the response to it, potentially threatens our society and that is an entirely different matter.

Properties of Explosives and Their Application Part 3

Energetic materials in general and explosives in particular are incredibly important to an industrial/technological society. For propellants it's their ability to produce large volumes of gas in a short time frame during combustion. Rocket motors put our satellites in space that provide us with other forms of important technology. The airbags in your car are nothing more than an energetic material undergoing rapid combustion to fill the bag. I don't think you want to know what energetic material is probably in there.

The usefulness of explosives comes from the fast generation of gas, on the microsecond timeframe or less, that provides a large power density and amount of work available. This allows us to do extensive momentum transfers for a relatively low cost (blasting for mining and construction). The metals production industry, and subsequent manufacturing industries heavily depend on the low cost production of raw materials. The power densities in explosives allow for the high velocity acceleration of metals which produces the shaped charge effects needed in oil and gas well completion.